This is Agave montana, also known as Hardy Century Plant, and Mountain Agave. This plant is referred to as the Queen of Agaves, and is perfect for growing in cold wet climates. This is not a desert cactus, and can survive damp environments and a temperature as low as 5F. The powdery looking green leaves have red colored edges and tips. In its last season this plants leaves will turn bright red leading up to and during blossoming. Agave plants have four parts that are edible. The flowers, leaves, stalks, and the sap or agave nectar. During this plants final season it will produce several pounds of edible flowers. The stalk can be harvested in the Summer just before the blossom is produced, and eaten in a similar way as to which sugarcane is eaten. Several Agave plants do support several different butterflies, but this particular Agave was not discovered until recently, and there is no research on which butterflies use this plant at this time. I expect several different rare butterflies would use this plant because those are the unusual and seldom seen butterflies that use the other Agave plants which are documented. This plant is even more hardy than Agave americana. USDA Hardiness Zones 7b to 9